Rearrange things to remove Windows build warnings and fmt better

Author: anacrolix

src/env.rs

@@ -1,26 +1,33 @@
 use cfg_if::cfg_if;
 
+fn emulate_freebsd_from_env() -> bool {
+    use once_cell::sync::OnceCell;
+    static CELL: OnceCell<bool> = OnceCell::new();
+    *CELL.get_or_init(|| {
+        let emulate = !matches!(
+            std::env::var("POSSUM_EMULATE_FREEBSD"),
+            Err(std::env::VarError::NotPresent)
+        );
+        if emulate {
+            super::error!("emulating freebsd");
+        }
+        emulate
+    })
+}
+
+/// FreeBSD doesn't support file range locking or block cloning (yet). We can emulate FreeBSD on
+/// platforms that have flock().
 pub(crate) fn emulate_freebsd() -> bool {
     cfg_if! {
         if #[cfg(target_os = "freebsd")] {
             true
         } else {
-            use once_cell::sync::OnceCell;
-            static CELL: OnceCell<bool> = OnceCell::new();
-            *CELL.get_or_init(|| {
-                let emulate =                 !matches!(
-                    std::env::var("POSSUM_EMULATE_FREEBSD"),
-                    Err(std::env::VarError::NotPresent)
-                );
-                if emulate {
-                    super::error!("emulating freebsd");
-                }
-                emulate
-            })
+            emulate_freebsd_from_env()
         }
     }
 }
 
+/// Whether to use flock() instead of file segment locking. flock() is not available on Windows.
 pub(crate) fn flocking() -> bool {
     emulate_freebsd()
 }

src/sync.rs

@@ -6,9 +6,9 @@ use shuttle::sync;
 #[cfg(not(shuttle))]
 use std::sync;
 
-pub use sync::*;
 use sync::Mutex as InnerMutex;
 use sync::MutexGuard as InnerMutexGuard;
+pub use sync::*;
 // These types work in any sync context.
 use std::sync::{LockResult, PoisonError};
 

src/sys/mod.rs

@@ -15,8 +15,6 @@ pub use flock::*;
 pub(crate) use pathconf::*;
 pub use punchfile::*;
 
-use crate::env::{emulate_freebsd, flocking};
-
 cfg_if! {
     if #[cfg(windows)] {
         mod windows;
@@ -75,30 +73,3 @@ pub trait FileSystemFlags {
 pub trait DirMeta {
     fn file_system_flags(&self) -> io::Result<impl FileSystemFlags>;
 }
-
-struct UnixFilesystemFlags {}
-
-impl FileSystemFlags for UnixFilesystemFlags {
-    fn supports_sparse_files(&self) -> bool {
-        // AFAIK, all unix systems support sparse files on all filesystems.
-        true
-    }
-
-    fn supports_block_cloning(&self) -> Option<bool> {
-        // AFAIK there's no way to check if a filesystem supports block cloning on non-Windows
-        // platforms, and even then it depends on where you're copying to/from, sometimes even on
-        // the same filesystem.
-        if emulate_freebsd() {
-            Some(false)
-        } else {
-            None
-        }
-    }
-}
-
-#[cfg(not(windows))]
-impl DirMeta for File {
-    fn file_system_flags(&self) -> io::Result<impl FileSystemFlags> {
-        Ok(UnixFilesystemFlags {})
-    }
-}

src/sys/unix.rs

@@ -1,9 +1,40 @@
+use std::fs::File;
+use std::io;
 use std::path::Path;
 
 pub(crate) use nix::errno::errno;
+use crate::sys::{DirMeta, FileSystemFlags};
+
+use crate::env::{emulate_freebsd};
 
 pub fn path_disk_allocation(path: &Path) -> std::io::Result<u64> {
     let metadata = std::fs::metadata(path)?;
     use std::os::unix::fs::MetadataExt;
     Ok(metadata.blocks() * 512)
 }
+
+struct UnixFilesystemFlags {}
+
+impl FileSystemFlags for UnixFilesystemFlags {
+    fn supports_sparse_files(&self) -> bool {
+        // AFAIK, all unix systems support sparse files on all filesystems.
+        true
+    }
+
+    fn supports_block_cloning(&self) -> Option<bool> {
+        // AFAIK there's no way to check if a filesystem supports block cloning on non-Windows
+        // platforms, and even then it depends on where you're copying to/from, sometimes even on
+        // the same filesystem.
+        if emulate_freebsd() {
+            Some(false)
+        } else {
+            None
+        }
+    }
+}
+
+impl DirMeta for File {
+    fn file_system_flags(&self) -> io::Result<impl FileSystemFlags> {
+        Ok(UnixFilesystemFlags {})
+    }
+}

src/tests.rs

@@ -10,8 +10,7 @@ use crate::testing::*;
 
 pub(crate) fn check_concurrency(
     f: impl Fn() -> anyhow::Result<()> + Send + Sync + 'static,
-    #[allow(unused_variables)]
-    iterations_hint: usize,
+    #[allow(unused_variables)] iterations_hint: usize,
 ) -> anyhow::Result<()> {
     #[cfg(loom)]
     {